Magnetic anisotropy Table

In Tabled theoretical magnetic anisotropies AK for selected molecules, calculated assuming the bond lengths shown in Fig. 5, are listed (in units of d.Kbenzene) d Compared with the experimental exaltations reported by Dauben et a/. . Theoretical values are in good agreement... 

Generally, protons attached to the a-carbon atoms of acyl silanes are somewhat deshielded relative to their carbon analogues (Table 2). Differences in magnetic anisotropy and electronegativity are no doubt responsible for this effect. It is interesting that a,/i-unsaturated acyl silanes appear to be an exception (entry 12). 

Table 44 Relationships among magnetic-anisotropy parameters for nearly-octahedral dn complexesa...

Magnetic anisotropies xlz (l/3)Tr/ for R = Ce-Yb except Pm, Gd (0.002 < AFj < 0.06, table 9) have been computed with eq. (58) and using five contact contributions Sfj (i = H9, H11-H14) and the geometrical G factors obtained from the crystal structures of (HHH)-[/ Co(L5)3]6+ (R = La, Lu). A qualitative good agreement (AF = 0.23) is obtained between the experimental magnetic anisotropies (scaled to -100 for Dy(III) and corrected for the variation of the crystal-field parameter near the middle of the series (vide supra), table 9) and Bleaney s factors (table 3). Further non-linear least-squares refinements of the molecular... 

Another illustrative example is that of phenylacetylene. Table 6-7 summarizes the H NMR chemical shifts of its alkyne H-atom in a variety of solvents [273], Most solvents (except aromatic solvents) decrease the shielding of the acetylenic hydrogen nuclei. The corresponding low-field shifts have been interpreted in terms of weak specific association between the alkyne as hydrogen-bond-donor and electron pair-donor groupings of the solvent [273], The high-field shifts in aromatic solvents arise from the magnetic anisotropy of the solvent molecules (see below). The order of effectiveness of the solvent... 

Vdues of the magnetic anisotropy are measured independently by n ans of the magnetic balance (58—60) and those of 22 are calculated (Table 3). The magnitude of ki2 is by far lower than elastic constants considered in defotmaticMis d ordinary solids. 

Figure 7.9a shows M-H hysteresis loops for a typical sample with the Cu underlayer (sample A). The substrate temperature was set at an elevated temperature of 345°C for the deposition of aU layers. The values of and squareness ratio (SQR) measured in the perpendicular direction are hsted in Table 7.1 together with the values of and of the SmCOj((X)2) reflection in an X-ray diffractometry, defined as the values of full width at half maximum obtained from the rocking curves. Both and SQR in the perpendicular direction were greater than those in the film plane, indicating that perpendicular magnetic anisotropy was clearly generated. The value... 

Fig. 7.9 M-H hysteresis loops of SmCOj thin films with perpendicular magnetic anisotropy, (a) Sample A, (b) sample B, and (c) sample C correspond to those in Table 7.1. Thick and thin lines represent the loops measured in the directions perpendicular and parallel to the film plane, respectively [45]...

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